On Thursday, the father of Akemi Adachi died in a hospital after being considered brain-dead since January. The father, 67, who suffered from diabetes, was hospitalized that month after he lost consciousness due to a low blood-sugar level, according to police.

Earlier this month, police accused Adachi of murder in the death of her brother, 40-year-old Masamitsu. On March 27, she plied him with sleeping pills at their family residence in Sakai City. She then allegedly killed him through carbon monoxide poisoning by burning charcoal briquettes in a bathroom.

Upon her arrest, Adachi denied the allegations. “I didn’t do it,” the suspect was quoted by police.

Immediately following the death of Masamitsu, the case was ruled a suicide by police. However, an examination of the body of Masamitsu revealed the presence of components of the sleeping pills. The components proved to be a match for pills prescribed to the suspect, police said.

After police found glue used to seal the bathroom with weather stripping and a lighter in a room outside the bathroom, police launched a murder investigation. As well, a will containing questionable wording was also found on the premises, police said.

Police had previously revealed that the brain-dead condition of the suspect’s father came as a result of an unnatural drop in insulin used to treat his diabetes. The day before her father was hospitalized, Adachi visited the residence to stay overnight. During that visit, she served him sake. Police are now investigating whether the suspect was behind the unnatural drop in the insulin.

Adachi is the president of Daiichi Suido, a waterworks company founded by the father. Police believe that the suspect and her brother got into a dispute over an inheritance.